INFO: task syz.0.8315:22264 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.8315 state:D stack:27288 pid:22264 tgid:22263 ppid:19034 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5282 [inline]
__schedule+0x14db/0x5030 kernel/sched/core.c:6894
__schedule_loop kernel/sched/core.c:6976 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6991
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7048
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:776
nfsd_nl_threads_get_doit+0x1b6/0x6f0 fs/nfsd/nfsctl.c:1678
genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:737
__sock_sendmsg net/socket.c:752 [inline]
____sys_sendmsg+0x577/0x880 net/socket.c:2610
___sys_sendmsg+0x21f/0x2a0 net/socket.c:2664
__sys_sendmsg net/socket.c:2696 [inline]
__do_sys_sendmsg net/socket.c:2701 [inline]
__se_sys_sendmsg net/socket.c:2699 [inline]
__x64_sys_sendmsg+0x19b/0x260 net/socket.c:2699
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1ea058f749
RSP: 002b:00007f1ea13e1038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f1ea07e5fa0 RCX: 00007f1ea058f749
RDX: 0000000004008090 RSI: 0000200000000140 RDI: 0000000000000003
RBP: 00007f1ea0613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1ea07e6038 R14: 00007f1ea07e5fa0 R15: 00007fffa2fd7cc8
Showing all locks held in the system:
1 lock held by rcu_exp_gp_kthr/18:
#0: ffff8880b863abe0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:644
1 lock held by khungtaskd/30:
#0: ffffffff8e344f60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e344f60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e344f60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by udevd/5193:
2 locks held by getty/5577:
#0: ffff88803401b0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x449/0x1460 drivers/tty/n_tty.c:2211
3 locks held by kworker/0:3/14741:
#0: ffff88801b015948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3254
#1: ffffc9000c98fc40 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3255
#2: ffffffff8e34a578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#2: ffffffff8e34a578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x36e/0x6e0 kernel/rcu/tree_exp.h:961
2 locks held by syz.8.7779/17428:
#0: ffffffff8f79df70 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e63c308 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x137/0x1660 fs/nfsd/nfsctl.c:1886
2 locks held by syz.0.8315/22264:
#0: ffffffff8f79df70 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e63c308 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_get_doit+0x1b6/0x6f0 fs/nfsd/nfsctl.c:1678
1 lock held by syz.1.8799/26824:
#0: ffffffff8e34a578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#0: ffffffff8e34a578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x36e/0x6e0 kernel/rcu/tree_exp.h:961
1 lock held by syz-executor/27557:
1 lock held by syz-executor/27562:
#0: ffffffff8f736048 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff8f736048 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xf95/0xfe0 kernel/hung_task.c:515
kthread+0x389/0x480 kernel/kthread.c:467
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 22346 Comm: syz.9.8321 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__kasan_check_write+0x0/0x20 mm/kasan/shadow.c:36
Code: 48 8b 0c 24 31 d2 e9 ef e4 ff ff 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 89 f6 48 8b 0c 24 ba 01 00 00 00 e9 bc e4 ff ff 66 66
RSP: 0018:ffffc9000fd16e98 EFLAGS: 00000293
RAX: ffffffff82322306 RBX: dffffc0000000000 RCX: ffff888045778000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88801de425c0
RBP: ffff88801de425c8 R08: ffffffff8232218e R09: ffffffff8e344f60
R10: 0000000000000010 R11: ffffffff81ad4f00 R12: 00000000000573ad
R13: 0000000000000001 R14: 0000000000000000 R15: ffff88801de425c0
FS: 0000000000000000(0000) GS:ffff8881259ad000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffca8446ff0 CR3: 0000000034300000 CR4: 00000000003526f0
Call Trace:
instrument_write include/linux/instrumented.h:40 [inline]
___clear_bit include/asm-generic/bitops/instrumented-non-atomic.h:44 [inline]
__update_page_owner_free_handle+0x1b3/0x470 mm/page_owner.c:288
__reset_page_owner+0x85/0x1f0 mm/page_owner.c:321
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1436 [inline]
free_unref_folios+0xcc0/0x13e0 mm/page_alloc.c:3033
folios_put_refs+0x584/0x670 mm/swap.c:1002
folio_batch_release include/linux/pagevec.h:101 [inline]
shmem_undo_range+0x49e/0x1490 mm/shmem.c:1138
shmem_truncate_range mm/shmem.c:1250 [inline]
shmem_evict_inode+0x26e/0xa70 mm/shmem.c:1380
evict+0x5f4/0xae0 fs/inode.c:837
__dentry_kill+0x209/0x660 fs/dcache.c:670
shrink_kill+0xa9/0x2c0 fs/dcache.c:1137
shrink_dentry_list+0x2e0/0x5e0 fs/dcache.c:1164
shrink_dcache_tree+0xca/0x2e0 fs/dcache.c:-1
do_one_tree+0x28/0xe0 fs/dcache.c:1644
shrink_dcache_for_umount+0xa0/0x170 fs/dcache.c:1661
generic_shutdown_super+0x67/0x2c0 fs/super.c:621
kill_anon_super+0x3b/0x70 fs/super.c:1289
deactivate_locked_super+0xbc/0x130 fs/super.c:474
cleanup_mnt+0x425/0x4c0 fs/namespace.c:1323
task_work_run+0x1d4/0x260 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x694/0x22f0 kernel/exit.c:971
do_group_exit+0x21c/0x2d0 kernel/exit.c:1112
get_signal+0x1285/0x1340 kernel/signal.c:3034
arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x2c1/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd9e39c2005
Code: Unable to access opcode bytes at 0x7fd9e39c1fdb.
RSP: 002b:00007fd9e1bf5f80 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007fd9e3be5fa0 RCX: 00007fd9e39c2005
RDX: 00007fd9e1bf5fc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fd9e3a13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007fd9e3be6038 R14: 00007fd9e3be5fa0 R15: 00007ffecbae3e78